1. Field of Invention
The present invention relates to a cargo supporting device in the field of mechanics.
2. Related Art
The cargoes have to be fixed to prevent from being slipped or displaced during transportation. In regards to ordinary convertibles, cargos could be bound directly by using ropes. However, the cargoes in containers or van trucks could not be positioned by ordinary ropes for purpose of transportation. In order to address such a problem, people have designed various kinds of tools including the cargo supporting device.
The cargo supporting device is comprised of an inner tube and an outer tube, in which the outer tube is partly covered on the inner tube. A handle is hinged to the outer tube. A pawl is provided on the inner end of the handle. The inner tube is provided with several teeth along the axial direction thereof. When the pawl of the handle is inserted among the teeth, the handle could be fixed in such a manner that the inner tube and the outer tube could be fixed and not be contracted any more.
A Chinese Patent Publication CN101531160A discloses a lock mechanism for a cargo supporting device including an inner tube and an outer tube, in which the inner end of the handle could be inserted among the teeth. When the handle is turned in one direction, the inner end of the handle would be disengaged from the teeth. When the handle is turned in the other direction, the inner end of the handle would be engaged with the teeth. Therefore, the outer tube could be fixed to the inner tube when the cargo supporting device is in operation. However, as the inner end of the handle has teeth in part, the teeth on the handle are engaged with the teeth on the inner tube in the connection state, and are separated from the teeth on the inner tube in the separation state. However, the teeth on the handle could be deadly locked with the teeth on the inner tube while the handle is turned, which brings about poor reliability of the cargo supporting device in use.